Choke-coil.



INVENTOH ATTORNEYS MOW. M, Li H M WW m N m a m r W 5D i P. C Y W F D :3F W WW Wm WWW j E mi J. w x: m a F, W H P a w w I 7 2%? m 5 N YWITNESSES ment of the cores.

.coils.

range of the coils may be obtained between the maximum and minimummovement of the cores. This adjustment of the terminal voltage is avital point in my invention, as in the ap lication of the coil it isnecessary to vary t e current, i. c., the voltage at the terminals ofthe coil, from the fact that it is necessary to have diilerent degreesof light at the picture. Some picture films are very dark and somelight, and hence the current supplied to the lamp must be increased ordecreased to provide for this variation.

There are several difierent methods which may be employed to accom lishthe adjust- That s own in Figs. 1 and 1 is deemed the simplest and bestand is made by the simple adjustment of the clamping nuts. The coils andcores, however, may be adjusted to and from each other by any suitablemeans.

The coils are so designed that the total losses do not exceed 250 watts,suilicient radiating surface being provided to take care of this heatloss.

As to the detail construction of the coils, the cores are made up ofabout 200 sheets of transformer iron of L-shape form seen in Fig. 2.This L-shape form prevents excessive leakage through the ends of thecopper in the copper coils and hence excessive heating. The iron coresare assembled as shown in Fig. 2, the idea being to so lead the magneticlines around the iron and across the air ga with minimum leakage.

he coils are form-wound and are placed over the cores and held inposition by the porcelain cleat F, securing the terminals J, c of thecoils.

As a modification o my invention, the design of the cores may be changedto the form shown in Fig. 3, in which A, B represent the cores in whichthe variable air gap is formed by means of the armatures R and it. Thisform requires separate iron armatures either at one or both ends of thecores. The adjustment of the terminal voltage is limited to the distanceapart oi" the iron cores, for when the armatures are moved beyond thedistance apart of the cores, the magnetic lines leak. across the cores,causing excessive heat in the coils and so limiting the variation ofSuch leakage causes eddy currentsthe voltage. This form of coil,however, is not so desirable as that shown in Fig. 2,'in which theL-shape core is ideal in respect to the adjustment and leakage; for inthe latter form as the cores are separated, to give greater current, thecoils are also separated, increasing the effective radiating surface forthe heat, at the same time the heating effect would be increased by thepassage of the larger current. The magnetic leakage is not increased, asthe end of the alwa s the closest to the other core.

I c aim 1. A choke coil comprising two cores with coils woundthereabout, and means for holding the same in a predetermined relationand adjusting one core and coil to the other core and coil to 1produce avariable air gap.

2. A cho e coil comprising two cores each having an L-shape extensionarranged at opposite ends to each other, two coils embracing said cores,and means for clamping the coils and cores in variable relation to eachother to reduce a variable air gap.

3. A c oke coil comprising'two laminated cores each having an L-shapedextension arranged at opposite ends to each other, two

coils embracing said laminated cores, and

means for clamping the coils and laminated cores in variab produce avariable air gap.

4. A choke coil comprising two. laminated cores each having an L-shapedextension arranged at opposite ends to each other, two coils embracingsaid laminated cores, two clamps for each end of the cores with clampingbolts for securing them to ether, the said ends of the cores beingextended beyond the coils and retained in adjustable position betweenthe clamps with a variable air gap between them.

5. A choke coil comprising two cores, two coils embracing said cores,two clam s for each end of the cores with clamping bo ts for securingthem together, the said ends of the cores being extended beyond thecoils and re tained in adjustable position between the clamps with avariable air ga between them.

LOUIS 0. LA GWORTHY.

Witnesses:

M. D. Burrme'ron, G. R. KNIGHT.

L-shape core is e relation toeach other to

